Current decision-making processes on scheduling of diagnostic and screening procedures, or dosage and frequency regimes for therapeutic procedures for Breast, Colon, Prostate, lung, and other solid tumors, are based on epidemiological data for patient categories discriminated by age, genetic risk, family history, and few personal clinical features which may limit the sensitivity of the screening apparatus, or the efficacy of the respective treatment.
One unknown in these decision-making processes is the patient-specific sojourn time of the disease in the phase to which the diagnostic or therapeutic procedure is intended to apply. The sojourn time is a function of the progression rate of the disease, and many of these procedures are optimal and most effective when synchronized with this rate. Lack of appropriate methods to predict progression rates for individual patients is the reason why sojourn times remain unknown. As a result, patients are often treated with “one size fits all” strategy, in which the sojourn times are calculated via statistical averages from the population. The best example for this strategy is the recent recommendation from the US Preventive Service Task Force that all women between 50 and 74 should go through bi-ennial mammogram screening. This recommendation may be optimal to some women, but will fail to early-detect those with fast progression rate, and will lead to unnecessary stress and excess radiation in those with slow progression rate.
Since the progression rates of solid tumors vary considerably between diagnosed patients, additional discriminatory measurements would have profound prognostic, diagnostic and therapeutic value, particularly for personalized medicine, and will ultimately lead to more informative diagnoses and more effective treatments and prognostics.
Contrary to global measures like BMI, which is mostly non-indicative for personalized medicine, the intracellular metabolic balance between oxidative phosphorylation, or OXPHOS (the production of ATP in the mitochondria by burning Pyruvate with Oxygen) and Glycolysis (the production of ATP in the cytosol by the breakdown of Pyruvate to Lactate without Oxygen) strongly affects disease progression rates, directly through biosynthesis and indirectly through enhancement of immune response, and thus provides a valuable personal diagnostic and therapeutic discriminant for the above decision-making processes. A possible context where this balance can become evident and measurable is aerobic exercise, where energy from aerobic and non-aerobic metabolism is concurrently produced in the skeletal muscles, yet while athletes use some metabolic markers during aerobic exercise to customize their training zones, so far there is no attempt to measure the intracellular metabolic balance between OXPHOS and Glycolysis in vivo in humans. Current research in animal models does involve measurement of this metabolic balance, but is directed solely at drug discovery, and not at predicting patient-specific progression rates and sojourn times in animals or in humans.
Thus, there remains a considerable need for methods that can conveniently predict patient-specific disease progression rates and sojourn times with metabolic markers, so that they can be incorporated into the current decision-making processes on prognostics, diagnostics and therapeutics of solid tumors.